1. Technical Field of Invention
The present invention pertains to a plate for fixation of broken bones. The osteosynthesis plate was designed to provide maximal stability over a bone fracture with a minimum of material and intrusion to the patient. The size of the shape of the fixation plate can be customized for each patient using a software application.
2. Description of Prior Art
U.S. Pat. No. 4,503,848 to Caspar, et al, issued Mar. 12, 1985 for an osteosynthesis plate shows a way to make possible the effective immobilization of pieces of bone with an osteosynthesis plate by making the longitudinal edges of the osteosynthesis plate diverge in the manner of a trapezoid, that the osteosynthesis plate be provided with two adjacent rows of slots for its screws, and that the orientations of the longitudinal axes of the slots in both rows diverge in the same directions as the diverging longitudinal edges of the osteosynthesis plate itself. The problem with this approach is that while this plate is a solid and stable structure adapted to fit the contours of many long bones, as a stabilizing structure it is over engineered as much of its solid material is not required to stabilize many common bone fractures throughout the body. A general rule of orthopedics is to find an implant that will perform adequately with a minimal volume and intrusion. In the case of osteosynthesis bone plates, stability of the fracture line is the primary concern of the implant as many complications stem from instability of the fracture region. These complications include infection, nonunion, and malunion of the fracture. While maximal stability of the fracture can be achieved through increasing the size and strength of the plate, there is both a limited number of materials capable of safe permanent implantation within the body and a limit to the size and shape of plates as increasing the volume of the plate can eventually cause complications due to the intrusive nature of the implant. Plate palpability, thermal sensitivity and stress shielding of bone are some complications incurred with plates of larger strength and volume. Furthermore, excessively large and stiff bone plates are cumbersome during surgery and can add significant time and cost to the procedure.
U.S. Pat. No. 5,372,598 to Luhr, et al, issued Dec. 13, 1994 describes the invention of a small bone plate suitable for use, for example, on the cranial skeleton, on the facial skeleton and on micro fragments of other skeleton sections. The bone plate is formed from webs joining screw hole boundaries in a particular fashion; and the plate can be bent in its plane, without deformation of the screw hole boundaries. The problem with this design is that it is a structure comprised solely of lateral bars that provide stability only in directions of compression and tension (pulling apart) within the fracture. An osteosynthesis plate for fractures should maximize stability by preventing relative movement of fractured bone pieces. Three major relative movements are seen in fractures of the mandible: separation or pulling apart of the fracture pieces in a direction normal to the plane of the fracture, lateral movement or shearing along the fracture plane in a direction approximately normal to the occlusal plane, and torsion of the fracture plane along the length of the mandible. The object of maximal osteosynthesis stabilization and minimal plate volume is only achieved through an optimal structure that combats all directions and moments of relative fracture movement.
U.S. Pat. No. 4,966,599 to Pollock, et al, issued Oct. 30, 1990 describes precontoured plating, screws, instruments and methods for osteosynthesis. Plates according to the present invention take advantage of the fact that human adult craniofacial structure and shape is highly similar among the population. The plates are thus preformed, pretempered, precontoured, and preconfigured during manufacture to fit a large proportion of the human adult population. The plates consequently require less time during surgery to twist and bend to conform to the skeletal structure and their crystalline and other structural characteristics need not be adversely affected by extensive bending, twisting and shaping in the operating room. The plates may be packaged and presented for use on forms which simulate portions of the skull so that their intended craniofacial location is easily recognized by members of the surgical team. In the case of the osteosynthesis plate used to fixate the mandibular ridge, the plate is contoured inappropriately. The part of the plate contacting the mandibular ramus should be situated further near to the anterior face of the ramus (which may require grinding the surface of the ridge), while the part of the plate contacting the mandibular body should be angled as much as possible so the screws remain nearer to the alveolar border of the mandible. The ideal form of the osteosynthesis plate is nearer to a mirror image of the plate described in Pollock.
U.S. Pat. No. 6,711,432 to Krause, et al, issued Mar. 23, 2004 describes the devices and methods for implementing computer aided surgical procedures and more specifically devices and methods for implementing a computer-aided orthopedic surgery utilizing intra-operative feedback. A three-dimensional model of an area of a patient upon which a surgical procedure is to be performed is modeled using software techniques. The software model is used to generate a surgical plan, including placement of multifunctional markers, for performing the surgical procedure. After the markers are placed on the patient, an updated image of the patient is taken and used to calculate a final surgical plan for performing the remainder of the surgical procedure. The three-dimensional modeling, surgical planning, and surgery may all take place remote from each other. The various entities may communicate via an electronic communications network such as the Internet. The problem with this method is that the software does not output any information as to the appropriate implant to use for the surgery nor does it output any information pertaining to the design parameters of an implant that would provide the best functioning for each patient. In the case of osteosynthesis, software of this nature should provide information describing design characteristics for an implant that will provide an environment for adequate fracture healing in each patient.
U.S. Pat. No. 6,772,026 to Bradbury, et al, issued Aug. 3, 2004 describes the rapid design and manufacture of biomedical devices such as implants, oral dosage pills and implantable pharmaceuticals employs electronic data and modeling transmissions via a computer network. Patient information and patient-specific radiological data is captured and transmitted via a computer network to a design and/or manufacturing site. A multi-dimensional digital model is created based on the radiological data and patient information. Communications interchanges between a clinical/diagnostic site and a design/manufacturing site permit modification of the digital model until approved. The approved digital model is converted into machine instructions to construct the biomedical device. Alternatively, the digital model is employed in a best fit selection of a biomedical device from a pre-existing set of biomedical devices or machine-instructions. Transmittal of data over computer networks is further directed to the use of a Website to perform various client-interaction and follow-up tasks. The problem with this method is that the design and customization process does not include an analysis that can optimize the design parameters of the biomedical implant based on analysis output measures that indicate the safety, adequacy, and intrusiveness of the implant. Sufficient stability of a bone fracture is required for adequate fracture healing. Instability or excessive movement in the presence of a foreign body can lead to infection and the subsequent nonunion of a fracture. An outcome of this type can require a second surgery to remove the hardware and provide more sufficient fixation. Furthermore, excessive stress imposed upon the osteosynthesis plate can lead to a failure of the plate, also requiring a second surgery. Adverse outcomes such as these can be avoided in employing a method using analysis of a model that includes patient specific data to determine the appropriate design parameters of an osteosynthesis plate that will lead to safe and adequate healing of a fracture.